Malaria is a caused by a single-celled parasite, belonging to the genus Plasmodium. There are about 5 species of Plasmodium that commonly infect human beings, usually transferred by a mosquito as it takes a blood meal for its developing young (Figure 6). From the mosquito’s salivary glands, an immature stage of Plasmodium is transferred into the human bloodstream, eventually entering the liver. After a period of dormancy, the infected liver cells burst, releasing a stage of the parasite that invades the red blood cells (RBCs), where they replicate asexually. Eventually, the large numbers of parasites cause the RBCs to burst, releasing the parasites (gametocytes) and various waste products. At this stage, the symptoms of malaria exhibit themselves. Gametocytes may be taken up in a second mosquito’s blood meal, infecting that mosquito and starting the cycle again.

Figure 6. Life Cycle of Plasmodium species that cause malaria. You can understand the basics of this life cycle, without learning all the stage names. Focus on the transfer from the mosquito to the human host, invasion and dormancy in the liver, bursting of liver cells releasing the life stage that infects RBC’s, rupturing of RBC’s and release of gamete stage, and uptake of these gametocytes by another mosquito taking a blood meal.

Sickle Cell Disease – Relief at last?

Malarial Disease

by George Shiflet
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